In classical droplet-merging calculations, the initial condition consists of
two droplets whose sharp-surfaces are touching, connected by tiny bridge
joining them.[1]} In our case, the bridge appears naturally, caused by the VdW mutual attraction.
This attraction is absent in any GP approach based on an atom-atom contact interaction, hence some initial velocity
has to be provided to the droplets or, alternatively,
the confining potential has to be modified in order to trigger the process.[2]}, [3]}
